scholarly journals The U2 snDNA Is a Useful Marker for B Chromosome Detection and Frequency Estimation in the Grasshopper Abracris flavolineata

2017 ◽  
Vol 151 (1) ◽  
pp. 36-40 ◽  
Author(s):  
Diogo Milani ◽  
Octavio M. Palacios-Gimenez ◽  
Diogo C. Cabral-de-Mello
Keyword(s):  
Evolutionary History ◽  
Frequency Estimation ◽  
B Chromosome ◽  
B Chromosomes ◽  
Future Studies ◽  
Functional Studies ◽  
Chromosome Transmission ◽  
Somatic Tissues ◽  
Frequency Changes

In this study, we describe a strategy to determine the presence of B chromosomes in the living grasshopper Abracris flavolineata by FISH using U2 snDNA as a probe in interphase hemolymph nuclei. In individuals without B chromosomes, (0B) 2 dot signals were noticed, corresponding to A complement U2 snDNA clusters. In +1B and +2B individuals, 4 or 8 additional signals were noticed, respectively. In all cases, the absence or presence of 1 or 2 B chromosomes correlated in hemolymph and in somatic or germline tissues, validating the efficiency of the marker. Our data suggest that the B chromosome of A. flavolineata is present in all somatic tissues. B-carrying individuals showed the same number of B chromosomes in germ and somatic cells, suggesting that the B is mitotically stable. The marker was used to compare B chromosome frequency in the analyzed population with a sample collected previously, in order to test for B frequency changes and differences of B chromosome prevalence among sexes, but no statistically significant differences were noticed. The identification of living animals harboring B chromosomes will be very useful in future studies of B chromosome transmission, as well as in functional studies involving RNA analysis, thus contributing to the understanding of evolutionary history and the possible role of the B chromosome in A. flavolineata.

scholarly journals B Chromosomes in Populations of Mammals Revisited

Genes ◽  
2018 ◽  
Vol 9 (10) ◽  
pp. 487 ◽  
Author(s):  
Mladen Vujošević ◽  
Marija Rajičić ◽  
Jelena Blagojević
Keyword(s):  
Mammalian Species ◽  
B Chromosome ◽  
Molecular Techniques ◽  
B Chromosomes ◽  
General View ◽  
Protein Coding ◽  
Host Parasite Interactions ◽  
Quantitative Characteristics ◽  
Host Parasite

The study of B chromosomes (Bs) started more than a century ago, while their presence in mammals dates since 1965. As the past two decades have seen huge progress in application of molecular techniques, we decided to throw a glance on new data on Bs in mammals and to review them. We listed 85 mammals with Bs that make 1.94% of karyotypically studied species. Contrary to general view, a typical B chromosome in mammals appears both as sub- or metacentric that is the same size as small chromosomes of standard complement. Both karyotypically stable and unstable species possess Bs. The presence of Bs in certain species influences the cell division, the degree of recombination, the development, a number of quantitative characteristics, the host-parasite interactions and their behaviour. There is at least some data on molecular structure of Bs recorded in nearly a quarter of species. Nevertheless, a more detailed molecular composition of Bs presently known for six mammalian species, confirms the presence of protein coding genes, and the transcriptional activity for some of them. Therefore, the idea that Bs are inert is outdated, but the role of Bs is yet to be determined. The maintenance of Bs is obviously not the same for all species, so the current models must be adapted while bearing in mind that Bs are not inactive as it was once thought.

Cooperation in primates

2015 ◽  
Vol 16 (3) ◽  
pp. 361-382 ◽  
Author(s):  
Anna Albiach-Serrano
Keyword(s):  
Observational Studies ◽  
Evolutionary History ◽  
Nonhuman Primates ◽  
Cooperative Behavior ◽  
Experimental Studies ◽  
Primate Species ◽  
Future Studies ◽  
History Of ◽  
Methodological Difficulties

Observational studies have suggested that some nonhuman primates’ cooperative behavior may rely on their capacity to share goals and understand the role of their partners. Experimental studies have tried to find evidence for this under controlled conditions, investigating aspects like the degree of organization in different primate species and the individuals’ capacity to recognize and choose good partners, switch roles with them, and care about their outcomes. Often, the results have been mixed. Partly, this is because of the methodological difficulties inherent to empirical research. In this paper, I offer a critical, methodological review of the experimental studies done in the last years on nonhuman primates’ cooperation, I discuss their findings, and suggest possible solutions to some of the procedural problems. Hopefully, this will contribute to improve the design of future studies and therefore our knowledge about the evolutionary history of cooperation.

Addressing Long-Standing Questions with Advanced Approaches: The 4th B Chromosome Conference

2020 ◽  
Vol 160 (3) ◽  
pp. 111-117
Author(s):  
Cesar Martins ◽  
Vladimir Trifonov ◽  
Andreas Houben
Keyword(s):  
Molecular Cytogenetics ◽  
B Chromosome ◽  
Research Field ◽  
B Chromosomes ◽  
Chromosome Research ◽  
Functional Studies ◽  
Sequencing Technologies ◽  
The Subject ◽  
Scientific Meetings ◽  
In The Beginning

B chromosomes (Bs) are enigmatic accessory genomic elements extensively characterized in diverse eukaryotes. Since their discovery in the beginning of the 20th century, B chromosomes have been the subject of investigation in laboratories all around the world. As a consequence, scientific meetings have dealt with B chromosomes, including the most specific and important conference in the field, “The B Chromosome Conference.” The 4th B Chromosome Conference (4BCC) took place in Botucatu, Brazil, in 2019 and was an excellent opportunity to discuss the latest developments in the B chromosome research field. B chromosome science has advanced from classical and molecular cytogenetics to genomics and bioinformatics approaches. The recent advances in next-generation sequencing technologies and high-throughput molecular biology protocols have led Bs to be the subject of massive data analysis, thus enabling the investigation of structural and functional issues not considered before. Although extensive progress has been made, questions are still remaining to be answered. The advances in functional studies based on RNA, epigenetics, and gene ontologies open the perspective to a better understanding of the complex biology of B chromosomes.

Elaborating the role of reflection and individual differences in the study of folk-economic beliefs

2018 ◽  
Vol 41 ◽  
Author(s):  
Kevin Arceneaux
Keyword(s):  
Decision Making ◽  
Individual Differences ◽  
Cognitive Processes ◽  
Evolutionary History ◽  
Behavioral Responses ◽  
History Of ◽  
Economic Beliefs

AbstractIntuitions guide decision-making, and looking to the evolutionary history of humans illuminates why some behavioral responses are more intuitive than others. Yet a place remains for cognitive processes to second-guess intuitive responses – that is, to be reflective – and individual differences abound in automatic, intuitive processing as well.

Ionic homeostasis and subcellular element compartmentation

1990 ◽  
Vol 48 (2) ◽  
pp. 150-151
Author(s):  
Ann LeFurgey ◽  
Peter Ingram ◽  
J.J. Blum ◽  
M.C. Carney ◽  
L.A. Hawkey ◽  
...  
Keyword(s):  
Leishmania Major ◽  
Ionic Homeostasis ◽  
X Ray ◽  
Functional Studies ◽  
Cell Compartments ◽  
X Ray Imaging ◽  
Resolution Electron ◽  
Multiple Cell ◽  
Role Of Zn

Subcellular compartments commonly identified and analyzed by high resolution electron probe x-ray microanalysis (EPXMA) include mitochondria, cytoplasm and endoplasmic or sarcoplasmic reticulum. These organelles and cell regions are of primary importance in regulation of cell ionic homeostasis. Correlative structural-functional studies, based on the static probe method of EPXMA combined with biochemical and electrophysiological techniques, have focused on the role of these organelles, for example, in maintaining cell calcium homeostasis or in control of excitation-contraction coupling. New methods of real time quantitative x-ray imaging permit simultaneous examination of multiple cell compartments, especially those areas for which both membrane transport properties and element content are less well defined, e.g. nuclei including euchromatin and heterochromatin, lysosomes, mucous granules, storage vacuoles, microvilli. Investigations currently in progress have examined the role of Zn-containing polyphosphate vacuoles in the metabolism of Leishmania major, the distribution of Na, K, S and other elements during anoxia in kidney cell nuclel and lysosomes; the content and distribution of S and Ca in mucous granules of cystic fibrosis (CF) nasal epithelia; the uptake of cationic probes by mltochondria in cultured heart ceils; and the junctional sarcoplasmic retlculum (JSR) in frog skeletal muscle.

Mesophyll conductance: the leaf corridors for photosynthesis

2020 ◽  
Vol 48 (2) ◽  
pp. 429-439 ◽  
Author(s):  
Jorge Gago ◽  
Danilo M. Daloso ◽  
Marc Carriquí ◽  
Miquel Nadal ◽  
Melanie Morales ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Current Knowledge ◽  
Main Role ◽  
Mesophyll Conductance ◽  
Future Studies ◽  
Cell Structures ◽  
Leaf Tissues ◽  
Change Framework ◽  
Chloroplast Stroma

Besides stomata, the photosynthetic CO2 pathway also involves the transport of CO2 from the sub-stomatal air spaces inside to the carboxylation sites in the chloroplast stroma, where Rubisco is located. This pathway is far to be a simple and direct way, formed by series of consecutive barriers that the CO2 should cross to be finally assimilated in photosynthesis, known as the mesophyll conductance (gm). Therefore, the gm reflects the pathway through different air, water and biophysical barriers within the leaf tissues and cell structures. Currently, it is known that gm can impose the same level of limitation (or even higher depending of the conditions) to photosynthesis than the wider known stomata or biochemistry. In this mini-review, we are focused on each of the gm determinants to summarize the current knowledge on the mechanisms driving gm from anatomical to metabolic and biochemical perspectives. Special attention deserve the latest studies demonstrating the importance of the molecular mechanisms driving anatomical traits as cell wall and the chloroplast surface exposed to the mesophyll airspaces (Sc/S) that significantly constrain gm. However, even considering these recent discoveries, still is poorly understood the mechanisms about signaling pathways linking the environment a/biotic stressors with gm responses. Thus, considering the main role of gm as a major driver of the CO2 availability at the carboxylation sites, future studies into these aspects will help us to understand photosynthesis responses in a global change framework.

Motives for Social Isolation Following a Negative Emotional Episode

2018 ◽  
Vol 77 (3) ◽  
pp. 127-131
Author(s):  
Gérald Delelis ◽  
Véronique Christophe
Keyword(s):  
Social Isolation ◽  
Social Affiliation ◽  
Semantic Categorization ◽  
Future Studies ◽  
Cognitive Regulation ◽  
Emotional Event ◽  
Regulation Strategies ◽  
Emotional Events

Abstract. After experiencing an emotional event, people either seek out others’ presence (social affiliation) or avoid others’ presence (social isolation). The determinants and effects of social affiliation are now well-known, but social psychologists have not yet thoroughly studied social isolation. This study aims to ascertain which motives and corresponding regulation strategies participants report for social isolation following negative emotional events. A group of 96 participants retrieved from memory an actual negative event that led them to temporarily socially isolate themselves and freely listed up to 10 motives for social isolation. Through semantic categorization of the 423 motives reported by the participants, we found that “cognitive clarification” and “keeping one’s distance” – that is, the need for cognitive regulation and the refusal of socioaffective regulation, respectively – were the most commonly and quickly reported motives for social isolation. We discuss the findings in terms of ideas for future studies aimed at clarifying the role of social isolation in health situations.

scholarly journals The RelA hydrolase domain acts as a molecular switch for (p)ppGpp synthesis

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Anurag Kumar Sinha ◽  
Kristoffer Skovbo Winther
Keyword(s):  
Active Sites ◽  
Molecular Switch ◽  
Cell Physiology ◽  
Synthetase Activity ◽  
Wild Type ◽  
Functional Studies ◽  
Loop Region ◽  
A Site ◽  
Trna Binding

AbstractBacteria synthesize guanosine tetra- and penta phosphate (commonly referred to as (p)ppGpp) in response to environmental stresses. (p)ppGpp reprograms cell physiology and is essential for stress survival, virulence and antibiotic tolerance. Proteins of the RSH superfamily (RelA/SpoT Homologues) are ubiquitously distributed and hydrolyze or synthesize (p)ppGpp. Structural studies have suggested that the shift between hydrolysis and synthesis is governed by conformational antagonism between the two active sites in RSHs. RelA proteins of γ-proteobacteria exclusively synthesize (p)ppGpp and encode an inactive pseudo-hydrolase domain. Escherichia coli RelA synthesizes (p)ppGpp in response to amino acid starvation with cognate uncharged tRNA at the ribosomal A-site, however, mechanistic details to the regulation of the enzymatic activity remain elusive. Here, we show a role of the enzymatically inactive hydrolase domain in modulating the activity of the synthetase domain of RelA. Using mutagenesis screening and functional studies, we identify a loop region (residues 114–130) in the hydrolase domain, which controls the synthetase activity. We show that a synthetase-inactive loop mutant of RelA is not affected for tRNA binding, but binds the ribosome less efficiently than wild type RelA. Our data support the model that the hydrolase domain acts as a molecular switch to regulate the synthetase activity.

scholarly journals Germline variant in REXO2 is a novel candidate gene in familial pheochromocytoma

2020 ◽  
Vol 102 ◽  
Author(s):  
Yael Laitman ◽  
Shay Tzur ◽  
Ruben Attali ◽  
Amit Tirosh ◽  
Eitan Friedman
Keyword(s):  
Allelic Imbalance ◽  
Chromosomal Region ◽  
Cancer Susceptibility ◽  
Functional Studies ◽  
Cancer Susceptibility Genes ◽  
Whole Exome ◽  
Familial Pheochromocytoma ◽  
The Family ◽  
Recombination Processes

Abstract Pheochromocytoma (PCC) is a rare, mostly benign tumour of the adrenal medulla. Hereditary PCC accounts for ~35% of cases and has been associated with germline mutations in several cancer susceptibility genes (e.g., KIF1B, SDHB, VHL, SDHD, RET). We performed whole-exome sequencing in a family with four PCC-affected patients in two consecutive generations and identified a potential novel candidate pathogenic variant in the REXO2 gene that affects splicing (c.531-1G>T (NM 015523.3)), which co-segregated with the phenotype in the family. REXO2 encodes for RNA exonuclease 2 protein and localizes to 11q23, a chromosomal region displaying allelic imbalance in PCC. REXO2 protein has been associated with DNA repair, replication and recombination processes and thus its inactivation may contribute to tumorigenesis. While the study suggests that this novel REXO2 gene variant underlies PCC in this family, additional functional studies are required in order to establish the putative role of the REXO2 gene in PCC predisposition.

scholarly journals Repetitive DNA landscape in essential A and supernumerary B chromosomes of Festuca pratensis Huds

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Rahman Ebrahimzadegan ◽  
Andreas Houben ◽  
Ghader Mirzaghaderi
Keyword(s):  
Repetitive Sequences ◽  
Nuclear Genome ◽  
B Chromosome ◽  
B Chromosomes ◽  
Festuca Pratensis ◽  
Ltr Retrotransposons ◽  
Chromosome Identification ◽  
Satellite Repeats ◽  
Low Pass ◽  
Illumina Sequence

AbstractHere, we characterized the basic properties of repetitive sequences in essential A and supernumerary B chromosomes of Festuca pratensis Huds. This was performed by comparative analysis of low-pass Illumina sequence reads of B chromosome lacking (−B) and B chromosome containing (+B) individuals of F. pratensis. 61% of the nuclear genome is composed of repetitive sequences. 43.1% of the genome are transposons of which DNA transposons and retrotransposons made up 2.3% and 40.8%, respectively. LTR retrotransposons are the most abundant mobile elements and contribute to 40.7% of the genome and divided into Ty3-gypsy and Ty1-copia super families with 32.97% and 7.78% of the genome, respectively. Eighteen different satellite repeats were identified making up 3.9% of the genome. Five satellite repeats were used as cytological markers for chromosome identification and genome analysis in the genus Festuca. Four satellite repeats were identified on B chromosomes among which Fp-Sat48 and Fp-Sat253 were specific to the B chromosome of F. pratensis.

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